Refrigerator-motor-lubricating system



June l0, 1930. A A KUCHER 1,763,162

REFRIGERATOR MOTOR LUBRICATING SYSTEM original Filed oct. 1925 44 INVENToR lATTQRNEY `Patented June 10, 1930 UNITED STATES PATENT OFFICE ANDREW A.'K`UCHER, OF CHESTER',` PENNSYLVANIA, ASSIGNOR T0 'WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION F PENNSYLVANIA REE:EIGERAToR-Mo'roR-:LUERICATING SYSTEM v l.Application iled October 13, 1925, Sierial No. 62,275. Renewed January 21,V 1928.

My Ainvention relates to the lubrication of electric motors and particularly to those motors which are employed for driving the compression mechanisms of small capacity refrigerating machines such as are suitable for household use and it has 'for an object to provide a novel 'method and means for effectively lubricating the Working parts of such motors continuously and reliably for extended periods of time without care or attention. It has -for a further object to pro# vide adequate means fcr confining the lubricant to the bearings and the working partsl of the motor exclusively and for preventing leakage of the lubricant upon the current bearingportions of the motor.

These and other objects, which will be made apparent throughout the further description of my invention, may be attained by the employment of the apparatus here inafter describedand illustrated in the ac'- conpanying drawing in which the single iigure is a view, in sectional elevation, showing a refrigerating machine of the compression type in which the motor lubricating system is arranged in accordance with my invention.

Compression refrigerators normally com-l prise a' chamber in which a working fluid is evaporated at a relatively low pressure and temperature, a chamber in which the vapors are condensed at a high pressure and temperature, a compression mechanism for translatin theV vapors from thev evaporating cham er to the condensing chamber, and a valved conduit for returning the condensed iiuid at a reduced pressure into the evaporation chamber..

vThe compression mechanism, consisting esl sentially of a motor' and a compressor, 1s-

preferably housed within a single fluid tight chamber, as such an arrangement avoids the use of a stuffing box between the compressor and the motor, prevents leakage of the refrigerating fluid, insures quiet operation, and provides a very compact organization. With the motor totally enclosed in this manner, some means for lubricating it must be provided whichv will operate without attention continuously and reliably for long periods of time as, for example, one to two years.

This problem of lubricating the working parts of an enclosed refrigerator motor is especially diiicult where motors of the commutator type are employed and where the depositing of only a small amount of lubri f tion specically relates.

Referring to the drawing for a, description of my invention, I show the condensing chamber of a compression refrigerating machine of the type disclosed in la copending application of mine, lserially numbered 509,672,

` filed October 22, 1921 and entitled Refrigeration machine and in which Vmy novel method of lubrication may be carried out. It is to be understood that this invention may be practiced in other types of compression machines and that the apparatus illustrated and herein described is employed by Way of example and as an'aid in presenting a clear exposition o'f my invention. As illustrated, 10 designates acondensing chamber.

A compressor 11 driven by a suitable Amotor ,l

12 is disposed within the chamber. The condensing chamber 10 comprises a bell or dome, 13, secured to a base plate -14 as by bolts- 15. Supported upon the base late 14 is an inverted cup-shaped casting 16 orming a housing .for the motor, and super-imposed thereon is a receptacle 1'( which houses the compressor 11 and serves as a collection chamber for the liquid working fluid discharged by the compressor. y Suspended from the base plate 14 is a removable cup-shaped casting 18 for permitting renewal of the commutator brushes associated with the motor.

The motor shaft 21 is secured to the'compresser shaft 22 by a suitable key'23 thus producing, in eect, a common shaft..v This shaft is supported by a lower bearing 24 provided -in the casting 18, an intermediate bearing 25 provided in the upper portion of the casting 16 and an-upper bearing 26 provided in the compressor. The compressor 1s provided with an inlet port- 28 and a discharge chamber. The condensed fluid the condensing chamber.

tric cups 50 and 50 in the outer portion of the cup 50 uid through the small 5 compressor. The receptacle 17 communicates with the condensing chamber 10 through an outlet 38 provided in its upper portion for the passage of refrigerant vapor and through an opening 39 for permitting excess liquid 10 4working fluid to overflow.

Condensing coils 40 are arranged in the upper part of the dome 13 which are provided with an inlet connection 41 and an outlet connection (not shown) which pass without the is conveyed to one or more evaporators 43 by a conduit 44, the flow through the conduit 44 being controlled by a float valve 45 in order that a constant body of liquid may be maintained in Refrigerant vapor 1s removed from the evaporator 43 by a conduit 46 and conveyed to a surge tank 47 containing a body of liquid refrigerant having a level such as indicated at 48. The conduit 46 25 isso arranged with respect to the surge tank that it communicates with the surge tank at a point below 'the liquid level 48. The surge i ytank 47 may be of circular conformation and has disposed therein inner and outer concenwhich may be supported upon the conduit 44 and which have their upper portions extending above the level of the liquid 48. Provided in the inner cup is a small opening or aperture 49 'while provided is a plurality of relatively large circumferentially spaced openings 5l. The inner and outer cups 50 and 50 define, what may be termed, a tranquil chamber 52 whereby the flow of liqaperture 49 is not influenced by the turbulence of the liquid contained in the main body of the surge tank 47. Extending downwardly from the upper portion of the surge tank and concentrically dis- `4.5 posed between the conduit 44 and the cup 50 is an outlet conduit 53 having its entrant portion located at 54 for conveying refrigerant vapor from the surge tank 47 to a passage 55 communicating with the suction port 28 of the 50 compressor. An electric cable 56 for furnishing current to the motor passes through a liuid tight plug 57 provided in the base plate 14.

An inverted tube 61 is provided for sup- V plying the upper shaft bearing 26 with lubricant. This tube has an open inlet and has its discharge communicating with a cylindrical passage 62 arranged coaxially with the shaft. A groove 63 conveys the lubricant into the oo upper bearing 26 and it is discharged at the lower end of the bearing to the compressor. It percolates through the various clearances provided in the working parts of the compressor to the upper surface of the casting 16,

05 and a portion-thereof feeds downwardly in a casting. The circular groove 66 communicates through a radially disposed opening 67 y and a hollow portion 68 of the compressor shaft with a conduit 69 which extends downwardly into the hollow motor shaft 21.

An oil catcher 71 is secured to a jacket 72 provided on the motor shaft 2l in order to prevent lubricant which may seep past the circular groove 66 from falling upon the armature windings of the motor. The lubricant is drained from the oil catcher 71 by means of an opening 72 and a longitudinal groove 73 which communicates with the bore of the motor shaft 2l.

A circular recess 74 is provided in the cup shaped casting 18 for receiving lubricant discharged from the lower end of the motor shaft. The circular recess 74 communicates with an annular opening 75 formed by ball retainer rings 76 and 77 of the bearings 24. It further communicates through an opening 78 with an annular passage 79 which, in turn, is drained by means of a conduit 81. The conduit 81 is connected, as shown, to the upper portion of the surge tank 47 for draining the lubricating Huid thereto. The lower surface of the annular passage 79 is disposed a slight distance below the center line of the balls 82, and a level of lubricant corresponding thereto is consequently maintained about the bearing. This construction provides ample lubrication for the bearing and prevents such an accumulation of lubricant as might possibly interfere with the successful operation of the motor.

In order to further guard against lubricant being carried upwardly along the shaft and coming in contact with the current bearing portions of the motor, I interpose a series of baflies between the motor Aandthe bearing 24. I have found from experiment, that upon a stoppage of the apparatus, the pressure immediately attempts to equalize between the condensinfr chamber and the motor ,chamber, thereby causing the fluid to flow in a backward direction through the passage 55 and conduit 53. However, by leading the drain conduit 81 into the surge tank, this back-flow of gas is prevented from spraying lubricant into the motor chamber through the conduit 81 because of the relatively large volume of the surge tank and its capacity to absorb the change in pressure. However, as an added precaution, I may provide a baille 82 which is snugly fitted in the boreof the casting 18. This baille extends over the inlet end of the conduit 81 and should any lubrim stricted by al baffle 85 which' is fixed inthe casting 19 and through which the motor shaft extends, making a close clearance therewith. All of the structure heretofore described for supplying lubricant to the intermediate and lower bearings 24 and 25 and for preventing the lubricant supplied to these bearings-from coming into contact with the current bearing portions of the motor, with the exception of arranging the drain conduit 81 so as to com- 20 municate with the surge tank 47is shown in a copending application of mine serially numbered 643,364, filed June 4, 1923 and entitled Refrigeratoinl The operation of the above embodiment of my invention is as vfollows Upon starting the motor 12, the action of the compressor 11' produces a relatively low or sub-atmospheric pressure within-the evaporator 43. The pressure thusl produced is suficiently low to induce vaporization of the L, liquid refrigerant and heat is absorbed from the surrounding atmosphere through the walls `of the evaporator 43, the vapor thus' produced vpassing throughl the conduit 46 into the surge tank 47. Within the 'surge tank 47,

the vapor rises upwardly and is then drawn downwardly into the cup 50 to the entrant port 54 of the suction conduit 53 from whence it passes upwardly through the passage 55 to the inlet port 28 of the compressor.. During the passage of the refrigerant va or, a small quantity of liquid working uid drains through the aperture 49 into the interior of the cup and this liquid is entrained in the 45 refrigerant vapor passing to the compressor.

In this manner, a `constant circulation of the y i' liquid working fluid, which liquid is'rcomposed of both a refrigerant and a lubricant, is constantly maintained throughout the 50 evaporator 43 and surge tank 47 andthe segregation of the lubricant in thev evaporator 43l and the surge tank 47 is prevented. In addition, this liquid in passing through the compressor 11 lubricates and seals the same.l

"Ihe compressor 11 discharges refrigerant vapor removed from the surge tank 47 at an increased pressure through the conduit 35 and causes it to impinge against the balie 37. In this way, the liquid working fluid which is entrained in the refrigerant vapor is separated therefrom and fallsdownwardly into the receptacle 17, while the refrigerant vapor passes through the opening 38 into the condensing chamber. The liquid working fluid within the receptacle, being subject to the heat of the compressor, has its refrigerant component largely vaporized off, leaving a body of liquid containing a high percentage of lubricant. This novel-method of produc- -ing Aa iuid for lubricating .a refrigerating machine is disclosed'in a copending application of mine, serial number 643,364, filed June 4, 1923 and entitled Refrigeraton The hot refrigerant vapors after passing through the opening 38, come into contact with the coils 40 and are condensed by the cooling action thereof. rlhe condensed refrigerant falls to the lowerl portion of the condensing chamber and, upon suiicient rise of liquid level therein, the float valve 45 opens to permit a flow of liquid refrigerant through the conduit 44 directly to the evaporator 43. Any excess lubricating fluid which may accumulate within the receptacle 17 overflows through the outlet 39 and commingles with the condensed refrigerant in the condensing chamber 10 from whence it is conveyed through the conduit 44 to the evaporator 43 and is returned to the compressor 11 in the manner heretofore described.

Lubrication of the working parts of the compression mechanism is accomplished as follows:

The liquid working fluid contained in the receptacle 17, which has been subjected to the heat of the compressor and also to some of the heat of the motor and which therefore contains a high percentage of lubricant, is conveyed to the cylindrical opening 62 by the conduit 61 because the pressure prevailing within the compressor is relatively lower than that of the receptacle 17. The lubricant then feeds downwardly throu-ghl the working clearances normally provided in a compressor of this character and a considerable portion isdeposited upon the upper surface. of the motor housing16. For a more detailed description of the manner'in which the lubricant passes through the compressor 11, reference may be had to my lcopending application, serially numbered 260,487 and entitled Refrigerator compression mechanism. Because of the still lower pressure prevailing within the motof housing,the

-lubricant readily enters the groove 64 and the bearing 25 yafter `which a considerable portion is trapped within the circular groove 66 and is conveyed through the radial opening 67 to the hollow portion 68 of the c ompressor shaft from whence it is conveyed into the conduit 69 and thence to the bore of the. motor shaft 21.

A small quantity of lubricant may seep past the circular groove 66 and be discharged from the lower end of the bearing. This lubricant will be' deposited upon the upper end face of the motor shaft 21 whereupon it will be thrown outward, by the action of centrifugal force, into the lubricant catcher 71. From the lubricant catcher 71 the oil actionof the motor shaft drains inwardly-through the opening 72 and the groove 73 to the bore of the motor shaft 21, the static pressure of the oil accumulating in the catcher 71 being sufficient to compel constant drainage notwithstanding the slight opposing action created by the centrifugal 21. By the employment of such apparatus, the possibility of leakage of the lubricant upon the currentbearing portions of the motor is made very remote. I have found from experiment that my apparatus may be operated for extended periods of time without any of the lubricant coming into contact with the windings of the motor.

Lubricant discharged from the lower end of the motor shaft passes to the circular recess 74 and to the bearing 24; The lubricant is withdrawn from the bearing through the opening 78 which communicates with the conduit 81. As the level of the annular passage 79 is disposed slightly below the center line of the bearing 24, substantially one half of the bearing 24 is immersed in the lubricant at all times. This level of lubricant is sulficient to insure adequate lubrication of the bearing an'd is of such relatively small quantity that the possibility of a portion of it traveling upwardly to the windings of the motor is reduced to minimum.

As shown in the drawing, the conduit 81 is connected to the surge tank 47 and lubricant removed from the lower bearing 24 drains into the surge tank 47 andxis returned tothe inlet of the compressor by way of the aperture 49. The connection of the conduit -81 to the surge tank possesses numerous advantages in that machines of the household type are generally operated intermittently and that upon a stoppage of the machine there is an immediate tendency for the pressure in the condensing chamber and in the evaporator to equalize. In other words, there is a rush of pressure through the compressor 12 and its suction passage 55 into the surge tank 47 which, because of its relatively large volume, readily dampens this rush` of pressure and prevents the lubricant which may be contained in the conduit 81 from being sprayed backj into the motor chamber and over the motor. In addition, during the idle period of the machine, there is a gradual leakage of lubricant from the receptacle 17 downwardly into the working parts of the compressor and the intermediate bearing 25 to the lower bearing 24. In my arrangement this lubricant is drained into the conduit 81 and collects in the surge tank and of the motor of a vrefrigerating machine in ed. One very important feature of my invention resides in the fact that I maintain the discharge pressure of the compressor in the lubricant receptacle -while I maintain the suction pressure of the compressor in the motor housing and that I utilize this difference in pressure to compel the lubricant to pass through and to thoroughly lubricate the entire working parts of the motor.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are speciically set forth in the appended claims.

. What I claim is:

1. In a lubricating system for an intermittently operated fluid translating apparatus, the combination of a compressor, a receptacle for containing lubricant, means for repeatedly conveying lubricant from the receptacle to the compressor and back to the receptacle during the active periods of the compressor and for removing lubricant from the receptacle during at least portions of the inactive periods of said compressor, and a chamber for collecting the lubricant removed from thereceptacle during the inactive periods of said compressor. 1

2. In a lubricating system for an intermittently operated fluid translating apparatus, the combination of a compressor, a receptacle for containing lubricant, means motivated by the operation of the compressor for conveying lubricant from the receptacle to the compressor and thence back `to the receptacle during the active periods of the compressor and for removing lubricant from the receptacle during at least portions of the inactive periods of the compressor, a second receptacle for collecting the lubricant removed from the first receptacle during inactive periods of the compressor, and means for returning the co1- lected lubricant in the second receptacle to the first receptacle. 5

3. In alubricating system for an intermittently operated refrigerating apparatus, the combination of a condensing chamber, a compression mechanism disposed within the condensing chamber, a receptacle for supplying lubricant to the working parts of the compression mechanism during the operation of the machine, and a chamber associated with the compression mechanism for collecting the lubricant from dthe receptacle during the idle periods of the machine. Y

4. 'In a lubricating system for an intermittently operated refrigerating apparatus, the combination of acondenser, a compressor dis- Yposed within the condenser, a motor disposed below the compressor for driving the same,

' a receptacle disposed about the compressor chine, and a reservoir for containing the lubricant during the idle periods of the machine.

6. In a lubricating system for an intermittently operated refrigerating apparatustthe combination of a motor including a housing,

a compressor driven by the motor and superimposed upon the motor housing, a receptacle surrounding the compressor and containing a supply of lubricant during the operation of the machine, and a reservoir for collecting the Y lubricant during the idle periods of the ma-` chine, said reservoir having a capacity equal to or greater than the capacity of the lubri- 'cant receptacle. i.

7 In a lubricating system for an intermit# tently operated refrigerating apparatus, the combination of a compressor, a motor for driving the compressor, an evaporator, communicating means provided between the evaporator and the inlet of the compressor, a chamber adapted to collect lubricant provided in said communicating means, and a drainage yconnection provided between said chamber and the motor.

8. In alubricating system, the combination of a motor, a compartment, a compressor for removing vapor from the compartment, means for supplying lubricant tothe working parts of the motor, means for draining lubricant from the motor to the compartment, and means providedin the compartment for entraining the lubricant in the refrigerant vapor passing to the compressor.

9. In a lubricating system, the combination l of acompressor, a motor for driving the compressor, a receptacle, means for maintaining a body of lubricant under pressure in the receptacle, means subject to the pressure within the receptacle for delivering lubricant to the working parts of the motor, means for utilizing thecompressorto return the lubricant to the-receptacle, and a surge tank interposed in said return means, whereby upon a stoppage of the vmotor and a consequent.

- 10. In a lubricating system,the combinai tion of a motor, a fluid tight housing for the motor, a compressor driven by the motor, a receptacle containing lubricant and subject to the discharge pressure of the compressor, communicating means provided between the inlet of the compressor and the motor' hous ing for removing lubricant therefrom, means subject tothe difference in pressure between the inlet and the discharge of the compressor for conveying lubricant to the working parts of the motor, and a surge tank of substantial capacity located in the communicating means provided between the motor housing and the inlet of the compressor.

11. In a lubricating system for an intermittently operated refrigerating apparatus, the combination of a motor, a compressor driven by the motor, a receptacle containing a supply of lubricant for the compressor and the motor during the operation of the machine, and a reservoir for containing the lubricant during the idle periods of the machine.

12. In a lubricating system for an intermittently operated fluid translating apparatus, the combination of a compressor, a receptacle for containing lubricant,means responsive to the' operation of the compressor for circulating lubricant from the receptacle to the compressorand thence back to the receptacle during active periods of the compressor, means motivated by the pressures resulting from the operation of the compressor for removing lubricant from the receptacle during at least portions ofthe inactive periods of said compressor, and a second receptacle for collecting the lubricant removed from the first receptacle during the inactive periods of said compressor.

13. In a lubricating system for an intermittently operated Huid translating apparatus, the combination of a compression mechanism, a receptacle for supplying lubricant tothe compression mechanism during the active periods of the same as well as subsequent thereto, a reservoir for retaining the lubricant discharged from the compression mechanism during the inactive periods vof the same, and means for returning lubricant from the reservoir to the receptacle during active periods of the compression mechanism.

. In testimony whereof, I have hereunto subscribed my name this 7th day of October,

. r ANDREW A. KUCHER. 

